Hans Summers G0UPL and his new QMX: The Bob Crane W8SX FDIM Interviews Part 1 (audio)

http://qrp-labs.com/qmx.html

We are very pleased and grateful to present this year's series of Four Days in May interviews by our FDIM correspondent Bob Crane W8SX.   Once again Bob did an outstanding job interviewing the FDIM participants. 

In this interview, the amazing Hans Summers talks about his latest QRP Labs kit, the QMX.  It is a combination of the QCX Mini and the QDX.  

Hans explains the M:  QMX. The M is for Marriage. Magnificent. Merger. Marvelous, many things like that. It’s what you get when you marry the mechanical and conceptual design of QCX-mini, with the SDR, multi-band digital implementation of QDX. Simply: QDX + QCX-mini = QMX. 

It has a very clever switching power supply that automatically adjust to prevent spurs and harmonics from the power supply from appearing in the band of interest. 

I was especially interested in his plans to implement an SSB option in future software updates.  Hans will use the same very complicated SSB generation scheme used in the trueSDX rig, but hopes to achieve higher performance and  improved signal quality due to the much more robust hardware of the QMX. 

Here is the interview: 

http://soldersmoke.com/G0UPL23.mp3

Here is the QRP Labs site about the QMX:  http://qrp-labs.com/qmx.html

Here is the QRP Labs web site: http://qrp-labs.com/

And here is a really wonderful and very current article by Hans on the evolution of QRP Labs and its rigs from 2010 right on up through 2023 and the QMX.  It is really interesting: 

http://qrp-labs.com/images/qmx/docs/fdim2023.pdf

Thanks to Bob Crane W8SX, Hans Summers G0UPL, and all of the FDIM organizers. 

Hans G0UPL-- Homebrew Hero

QRP Labs HQ Tour

Really cool to see Hans describe his QRP Labs workshop in Turkey.  Lots of soul in that worshop.  Thanks Hans.  

 And here is a 2022 Turkish media interview with Hans and his team in the workshop:  

Grayson Evans KJ7UM on the Ham Radio Workbench Podcast

 

OM Grayson was on the HRWB podcast with George Zaf and company. This was a really informative and entertaining session.  For example, when asked if special precautions are needed when working with thermatrons, Grayson replies, "Well, try not to swallow anything... and don't sit on the thermatrons."  Words to live by my friends.  Grayson's story about cooking Tektronix scopes in a refrigerator re-purposed as an oven (after cleaning the 'scope with a Home Depot power washer) is the kind of practical advice that readers of this blog REALLY NEED!  

But seriously, I learned a lot just listening to Grayson talk about thermatrons with George and the HRWB crew.  

The interview includes nice shout-outs to SolderSmoke, SPRAT/G-QRP, and Electric Radio magazine. 

Check it out:  https://www.hamradioworkbench.com/podcast/hollow-state-design

Stay to the end for some thermatron-related password management advice from George. 

Thanks to Grayson and to all the folks at HRWB. 

Global Collaboration: The uSDX -- A Multi-Mode QCX

Bill:

There is a new open source, home brew, multi band, multi mode QRP transceiver that grew out of the QRP Labs QCX. Through some serious magic it retains an efficient class E RF amplifier for sideband and digital modes. It crams impressive SDR capabilities into an Arduino. More info at https://groups.io/g/ucx/topics

The basic work appears to have been accomplished by Guido Ten Dolle PE1NNZ. It uses pulse width modulation of the PA supply voltage to transmit  modes other than CW while retaining class E efficiency and uses a direct conversion SDR receiver.

 https://github.com/threeme3/QCX-SSB .

There are several variants by different developers. I built a variant designed by Barbaros Asuroglu WB2CBA  

https://antrak.org.tr/blog/projeler/usdx-an-arduino-based-sdr-all-mode-hf-transceiver-pcb-iteration-v1-02/ that uses through hole components (mostly) and I'm pleased with it's performance. I also designed and 3D printed a case.

This has an interesting development process with contributions by many, including the usual gang of suspects: Hans Summers, Ashhar Farhan, Manuel DL2MAN, Kees K2BCQ, Allison KB1GMX and Miguel Angelo Bartie PY2OHH. I apologize to the many others whose names I didn't list.

The band switch multiband version by DL2MAN is even smaller, but with SMD components which I wasn't ready to tackle yet.

BTW - your podcast encouraged me to go in this direction. I built a BITX 40, a uBITX (sent you a pix of it in an old Heathkit Twoer case), U3S, QCX and now my first step from kits to built from plans.

73

Bob   KD8CGH

https://antrak.org.tr/blog/projeler/usdx-an-arduino-based-sdr-all-mode-hf-transceiver-pcb-iteration-v1-02/

QSO Today -- Episode 300 -- Panel Discussion

Congratulations to Eric Guth, 4Z1UG for reaching episode #300 on his QSO Today podcast.  To commemorate the event, Eric organized a panel discussion.   It was a real pleasure and honor to participate.   

Listen to it here:  https://www.qsotoday.com/podcasts/300

Thanks again Eric! 

Manhattan-style Vacuum Tubes: "An Evolution of Thermatron Homebrew Techniques" by Grayson Evans

Grayson Evans was at Dayton.  Scheduling problems prevented him from being interviewed by ace correspondent Bob Crane, but Grayson was kind enough to e-mail us the essence of his presentation.  And it is really wonderful.  He brings the advantages of the Manhattan construction technique (fast prototyping, all components on the same side of the board, easy modification) to the world of tubes (aka valves or, as Grayson prefers, thermatrons).  We also see in Grayson's work an admirable willingness to bridge the digital-analog design, to bring into his rigs the best of the old and the new.  Thanks Grayson!

Grayson writes:

An Evolution of Thermatron Homebrew Techniques

For a long time I have been trying to develop some techniques to prototype Thermatron projects as easily as the typical “Manhattan style” solid-state construction.  Thermatron projects you see now-a-days still use the traditional technique of mangling aluminum-drilling and mounting everything to a “bud” style chassis. This just takes too much time and my projects always look disappointing.

Fortunately, around two years ago, Rex Harper, W1REX, came to the rescue after hearing an earlier talk of mine and developed a set of thermatron socket pads. The MeTubes panel from QRPme consists of 10 prototype pads for thermatron sockets. The panel has v-scores for breaking the panel into single tube pads. The panel has pads for mini 7 & 9s, octal, compactrons and acorns. Awesome.

The best sockets to use with the pads are PCB style.  These provide a large pin area to bend out and solder to the pad (see photos). 

I pre-mount a dozen or so of the 7-pin and 9-pin sockets on MeTube pads so I have them ready to go when prototyping. The “crude” example below shows and 7 and 9-pin socket on one of my prototypes.  I think this was a microphone amp for my AM transmitter.  Pardon the mess.

The nice thing about the pads is that they provide plenty of room to tac solder lots of parts to a single pin–easy to add or remove parts.  This is a lot easier than using the traditional tube socket pin. 

Prototyping thermatrons in this way is FAST.  No more punching out holes to hold thermatron sockets in aluminum chassis!

But it is still nice to be able to have the thermatron on the “top” of the board and the components on the “bottom” of the board.  To do this and still use the MeTube pads, the thermatron has to be mounted on the other side.  I did this by mounting the socket through the MeTube pad.  This requires making a hole in the center of the pad to pass the socket through and then soldering the pins in the usual way.  This is way easier with PC mount thermatron sockets and make a very nice installation. 

This technique has some great advantages over using the traditional socket with pins.  The pad has a lot more room to mount components to each pin.  Normal thermatron socket pins are difficult to attach more than two wires and it’s a bit more difficult to get a good solder connection.  The pads are easy to solder to and allow components to be easily attached in any direction since the “socket” is now flat.

It is also easy to attach the socket/pad to a copper clad board.  The same hole must be made in the copper clad board to pass the top of the socket through, then the pad is superglued to the board in the regular way.  



This is another example of “right side up” thermatron mounting on a prototype test board for crystal filters.  I mounted a small “plug board” (not sure what you call these things) in the center to allow me to easily swap filter components.  Notice the acorn thermatron soldered direct to the pad.  The board works great, the filter design sucked.  I gave up.  Maybe too much distributed C.

I used this technique, combined with Roger Fell’s idea of using inverted aluminum chassis, to build my latest project, a QRP AM/CW transmitter.  I’ve been wanting to try out a few new ideas and this seemed like a good project to try them on.  I also wanted to build the transmitter in modular “blocks”, interconnected in a similar way to Rogers. It worked pretty good although I am still trying to get the thing to work right.  Even new construction techniques can’t cure my screwups.  BTW, the ANALOG VFO is ROCK SOLID.  +/- 10 Hz over 30 min.   Even I was impressed.  The Hartley oscillator is the best circuit for thermatron circuits by far.

I’ll send an update when I get it fully working on AM and CW.

73,

Grayson

TA2ZGE

Grayson Evans TA2ZGE on "QSO Today"

Eric 4Z1UG has a really great interview with Grayson Evans TA2ZGE.  I'm writing this as I listen.

My reactions:

I sympathized completely with his reaction to EE professors who insisted that current flows from positive to negative.  Indeed.  Let's turn those arrows in the diode and transistor symbols around!

I too stripped down a Heathkit VFO and rebuilt it from scratch.

I share Grayson's aversion to metal work.  Viva Manhattan!  

Here is the interview:

http://www.qsotoday.com/podcasts/ta2zge

Could Grayson's Arduino Thermatron Shield Protect Us From Digi Domination?

Something old, something new, eh Grayson?   The author of "Hollow State Design" is engaged in an (I suppose) admirable effort to bridge the gap between our beloved Thermatrons and those new-fangled Arduinos.  Here Grayson tries to explain and justify his flirtation with the dark side:

I want to do some experimenting with Thermatrons and Arduino.  Sound weird?  Maybe not.

I really like playing around with the Arduino even though it violates my ban on digital technology in my shop. (My excuse is I am trying to use it teach my son something he can use to get a job someday.)

Sure Grayson.  That's what they all say.  "I was doing it for the kid..." 

Kidding aside, that tube shield looks pretty cool.  And I like the MeTubes base for the Thermatron.

Turkish Knack

Mehmet making contact using a homebrew rig

Lots of great homebrew videos from MehmetTB5X:
https://www.youtube.com/user/pashanline/videos

And he has a really nice web site:
http://www.tb5x.com/
Google Chrome does a pretty good job translating from Turkish.

Back with the Sats: Catching Cubes with a Dongle

I've been playing around with a little $13 DVB-T SDR Dongle receiver.  These devices normally tune 24 MHz to 1.7 GHz, but I modified the first one I had so that it would tune the HF bands.   Pete then sent me another one, which I vowed to keep unmodified, thinking that it would be fun to use it to listen to the many small Cube-Sats that are up there.  Most have downlinks (and Morse Code beacons) in the 470 MHz range.   I whipped together a simple ground-plane antenna for this band (One 6 inch copper wire as the receive element with 4 five inch groundplane elements). 

 

I then went to the "Heavens Above" website, plugged in my location, and clicked on "Amateur satellites."  This gave me a very accurate schedule of satellite passes.  I started listening. 





First I heard (and saw in the HDSDR waterfall)  the CW beacon of the Prism satellite at 7:05 am EDT today.  Prism is from the University of Tokyo and was launched from Japan.

Then Cubesat XI-V at 0711 EDT.

Cubesat XI-IV was heard at 0813 EDT.  The Cubesats are from Japan and were launched from Russia.  

ITUsPAT was heard at 1422 EDT.  The I is for "Istanbul"

Finally,  I monitored a pass of the Japanese FO-29 satellite aka JAS-2 at 1611.  Wow, this was like old times on the RS-10 and RS-12 satellites.   Lots of CW and SSB stations in the downlink passband.   Lots of fun.

At 470 MHz the Doppler shift of a low-earth orbit satellite is quite noticeable, and helps confirm that you are in fact receiving sigs from an orbiting device.

I thought it was pretty cool to take a $13 DVB-T Dongle, connect it to a small, copper-wire antenna, and use it all to receive signals from some 4"x4"x4" cubes in orbit of the Earth.

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Drake 2B Filter Madness!

Wow, WB4HFN has ALL the details here: 

http://www.wb4hfn.com/DRAKE/DrakeArticles/HenryFilter01.htm

--------------------------------------------
Grayson:  Good to hear from you on this snowy morning in DC.   Wow, that's a bit of 2B history I hadn't heard of. Seems like a bit of overkill to me.  Maybe it was aimed at people who were unconvinced of the effectiveness of the LC filters?   Somehow, to me, it just doesn't seem right.  If you want more selectivity from a 2B, the thing to do is Q multiply using that socket on the back.  73  Bill 

--- On Wed, 1/23/13, Grayson Evans wrote:

From: Grayson Evans 
Subject: New info on the Drake 2B
To: "Bill Meara" 
Date: Wednesday, January 23, 2013, 1:43 PM

HI Bill, 

I was looking through the Dec. 1963 issue of 73 and came across an ad for a "New Mechanical Filter Modification Kit" for the 2A and 2B.  IT says "like magic the Drake becomes a truly superlative SSB receiver"  Model DMF-2 $29..  Says sold exclusively by Henry Radio, but does not say if they made it or not.  

Has a photo showing a module that plugs in (maybe a tube socket?) right behind the VFO.  Module has a mechanical filter (Collins I presume), two IF transformers and a tube (probably the tube it substitutes for).   I have been looking through a bunch of old CQ's and 73's, early 60's, and I only saw this one ad.  Probably a rare accessory, but how knows.

Thought you might be interested.  

Take care,

Grayson

TA2ZGE - Ankara, Turkey

KJ7UM

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Another Treasure Trove Discovered

Our man in Ankara, Grayson, KJ7UM, sent me links to the truly amazing web site of Dr. J.B. Calvert, Professor Emeritus of Engineering at the University of Denver. Great stuff!
Sorry about the Istanbul/Ankara mix-up Grayson. I must say, Istanbul sounds cooler and more exotic. Good luck with the beer OM.

...............................................

Hi Bill,

Thought I would pass along the web site of quite an amazing fellow. While not a ham, he is a homebrewer, experimenter, and total scientist.
Guys like this amaze me!
http://mysite.du.edu/~jcalvert/index.htm

This is the site of Dr. James Calvert. On his site are hundreds of "papers" (articles?) on hundreds of scientific topics, history optics, astronomy, etc. I have read quite a few and I am damn impressed with the guys style, and curiosity.
Check out his paper on vacuum tubes. I learned a hell of a lot from this about a subject I though I know pretty well.

Check out this link
http://mysite.du.edu/~etuttle/electron/elecindx.htm
and the section on tubes:
http://mysite.du.edu/~etuttle/electron/elect27.htm
It is excellent. Enough to keep me reading for years.

Thanks for the plug in your last podcast.
BTW, I live in Ankara (the capital). If i did live in Istanbul, parts would be much easier to get. Actually I have found a source of parts, but what I REALLY need is a good source of decent beer! TUrkey only has one beer and it sucks. Anyone want to send me a good beer I would be most appreciative (then I can homebrew much better!)!

Take care and keep poding

Grayson
KJ7UM/TA2 - Ankara, Turkey

........................................

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20